SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac8ce27952e155a9e6b7b4952e243e2f8887adcfd1e247ad1d7f87f0209116c5' 
  AND token = 'weWmIShKavaR1YnzMlpATFdXWSu0gs9k6OpJsB9cgHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}